<template>
  <el-select :value="valueTitle" :clearable="clearable" @clear="clearHandle">
    <el-input
      class="selectInput"
      :size="size"
      :placeholder="placeholder"
      v-model="filterText">
    </el-input>

    <el-option :value="valueTitle" :label="valueTitle" class="options">
      <el-tree
        id="tree-option"
        ref="selectTree"
        :accordion="accordion"
        :data="options.length?options:remoteData"
        :props="props"
        :node-key="props.value"
        :default-expanded-keys="defaultExpandedKey"
        :filter-node-method="filterNode"
        @node-click="handleNodeClick">
      </el-tree>
    </el-option>
  </el-select>
</template>

<script>
import request from '@/utils/request'

export default {
  name: 'MSelectTree',
  props: {
    url: { // 接口地址
      type: String,
      default: undefined
    },
    isEdit: { // 是否编辑模式
      type: Boolean,
      default: false
    },
    /* 配置项 */
    props: {
      type: Object,
      default: () => {
        return {
          value: 'id', // ID字段名
          label: 'name', // 显示名称
          children: 'children' // 子级字段名
        }
      }
    },
    /* 选项列表数据(树形结构的对象数组) */
    options: {
      type: Array,
      default: () => { return [] }
    },
    /* 初始值 */
    value: {
      type: [Number, String, Array],
      default: () => { return null }
    },
    multiple: { // 是否多选
      type: Boolean,
      default: false
    },
    size: { // medium/small/mini
      type: String,
      default: 'medium'
    },
    /* 可清空选项 */
    clearable: {
      type: Boolean,
      default: () => { return true }
    },
    /* 自动收起 */
    accordion: {
      type: Boolean,
      default: () => { return false }
    },
    placeholder: {
      type: String,
      default: () => { return '检索关键字' }
    }
  },
  data() {
    return {
      filterText: '',
      valueId: this.value, // 初始值
      valueTitle: '',
      defaultExpandedKey: [],
      remoteData: []
    }
  },
  watch: {
    value() {
      this.valueId = this.value
      this.initHandle()
    },
    filterText(val) {
      this.$refs.selectTree.filter(val)
    }
  },
  mounted() {
    if (this.url) {
      request({
        url: this.url,
        method: 'post',
        data: {
          pageNum: 1,
          pageSize: 10000
        }
      }).then(res => {
        if (res.code === 0) {
          this.remoteData = this.$util.getTree(res.data.rows)
        }
        this.$nextTick(() => {
          this.initHandle()
        })
      })
    }
  },
  methods: {
    // 初始化值
    initHandle() {
      if (this.valueId) {
        var node = this.$refs.selectTree.getNode(this.valueId)
        if (node) {
          this.valueTitle = node.data[this.props.label] // 初始化显示
          this.$refs.selectTree.setCurrentKey(this.valueId) // 设置默认选中
          this.defaultExpandedKey = [this.valueId] // 设置默认展开
        }
      }
      this.initScroll()
    },
    // 初始化滚动条
    initScroll() {
      this.$nextTick(() => {
        const scrollWrap = document.querySelectorAll('.el-scrollbar .el-select-dropdown__wrap')[0]
        const scrollBar = document.querySelectorAll('.el-scrollbar .el-scrollbar__bar')
        scrollWrap.style.cssText = 'margin: 0px; max-height: none; overflow: hidden;'
        scrollBar.forEach(ele => {
          ele.style.width = 0
        })
      })
    },
    // 切换选项
    handleNodeClick(node) {
      this.valueTitle = node[this.props.label]
      this.valueId = node[this.props.value]
      this.$emit('input', this.valueId)
      this.defaultExpandedKey = []
      this.$emit('change', this.valueId, node)
    },
    // 清除选中
    clearHandle() {
      this.valueTitle = ''
      this.valueId = null
      this.defaultExpandedKey = []
      this.clearSelected()
      this.$emit('input', null)
      this.$emit('change', null)
    },
    /* 清空选中样式 */
    clearSelected() {
      const allNode = document.querySelectorAll('#tree-option .el-tree-node')
      allNode.forEach((element) => element.classList.remove('is-current'))
    },
    filterNode(value, data) {
      if (!value) return true
      return data.name.indexOf(value) !== -1
    },
    getCurrentData() {
      var node = this.$refs.selectTree.getNode(this.valueId)
      if (node) {
        return node.data
      } else {
        return undefined
      }
    },
    getData() {
      return this.remoteData.length ? this.remoteData : []
    }
  }
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
  .el-scrollbar .el-scrollbar__view .el-select-dropdown__item{
    height: auto;
    max-height: 274px;
    padding: 0;
    overflow: hidden;
    overflow-y: auto;
  }
  .el-select-dropdown__item.selected{
    font-weight: normal;
  }
  ul li >>>.el-tree .el-tree-node__content{
    height:auto;
    padding: 0 20px;
  }
  .el-tree-node__label{
    font-weight: normal;
  }
  .el-tree >>>.is-current .el-tree-node__label{
    color: #409EFF;
    font-weight: 700;
  }
  .el-tree >>>.is-current .el-tree-node__children .el-tree-node__label{
    color:#606266;
    font-weight: normal;
  }
  .selectInput{
    padding: 0 5px;
    box-sizing: border-box;
  }
</style>
